The present invention relates generally to distillation apparatus and, more particularly, to distillation apparatus which utilizes or operates according to the so-called thermocompressor principle.
Distillation apparatus which operate according to the so-called thermocompressor principle are known and generally comprise a housing in which a boiling chamber for accommodating the liquid to be distilled is situated, heating means for heating the liquid in the boiling chamber, feed line means for conducting liquid to be distilled into the boiling chamber, output line means for removing distillate from the distillation apparatus, and means for imparting additional energy to the vapor produced from the liquid in the boiling chamber such that the temperature of the vapor at the output side of the apparatus is increased.
Conventional distillation apparatus utilizing the so-called thermocompressor principle generally operate as follows. The liquid to be distilled is heated in the boiling chamber whereupon it evaporates with the vapor moving into the upper portion of the boiling chamber and having a temperature of about 96.degree. C. The vapor so produced is drawn from the upper portion of the boiling chamber into a compressor which imparts additional energy thereto whereupon the temperature of the vapor increases at the output or delivery side of the compressor to about 105.degree. C. The steam at the increased temperature is then conducted in a helical tube through the boiling chamber wherein the vapor condenses into distillate whereupon the distillate is removed from the distillation apparatus. The condensing vapor of course releases at least a part of its heat energy to the liquid to be distilled accommodated within the boiling chamber.
Although such conventional distillation apparatus which operate according to the thermocompressor principle described above have the advantage of relatively low energy consumption, e.g., about 4 kw per 100 liters/hour of liquid to be distilled, certain disadvantages are also inherent in such operation. The greatest drawback of such conventional apparatus is the admittance of impurities into the evaporated distillate flowing through the compressor which of course prevents an absolutely pure distillate from being obtained. Moreover, such distillation apparatus of the prior art are exceedingly massive and bulky and create objectionable high noise levels during operation.
Improvements have been made in the conventional distillation apparatus which operate according to the thermocompressor principle as described above in that the temperature of the vapor produced in the upper regions of the boiling chamber is higher than 100.degree. C., usually about 105.degree. C., whereby the pressure in the boiling chamber will exceed atmospheric pressure. As a result thereof, the temperature of the vapor will increase to about 120.degree. C. at the output side of the compressor. However, in other respects, the various advantages and disadvantages of the improved distillation apparatus are the same as those discussed above in connection with the conventional distillation apparatus.
Also known in the art is distillation apparatus which operates in accordance with the thermocompressor principle and wherein the temperature of the vapor produced from the liquid to be distilled is increased utilizing a heat pump. In this arrangement two separate heat exchangers are utilized, one heat exchanger being situated in the upper region of the boiling chamber while the other heat exchanger is situated in the lower region of the boiling chamber. However, this arrangement is expensive in manufacture and requires a complex control mechanism for its operation.